Method concentrate and solution for simultaneous cleaning, degreasing and removal of the lubricant carrier layer from iron and steel workpieces

ABSTRACT

Alkaline concentrate and aqueous solution for removing lubricant carrier and residue from iron containing surfaces. The alkaline solution contains phosphate ions and either cobalt or nickel ions or a mixture of the two. Use of the solution helps prevent inter stage rusting and the problems resulting therefrom.

United States Patent Jorns 1 1 Dec. 2, 1975 1 1 METHOD CONCENTRATE ANDSOLUTION [56] References Cited FOR SIMULTANEOUS CLEANING, UNITED STATESPATENTS DEGREASING AND REMOVAL OF THE 2.499.261 2/1950 Roscnhloom 117/127 LUBRICANT CARRIER LAYER FR M IR N 2.813.075 11/1957 Brooke252/855 AND STEEL WORKPIECES 2.916.459 12/1959 Arnold 252/152 3.015.630l 1962 Th 252 101 [751 lnventor: Peter Jorns, Frankfurt am Main. 3J5 087911964 2521387 Germany 3.668.132 6/1972 Finder 134/2 [73] Assigneel yMeta] Industries Corporationq 3.723.334 3/1973 Maurer 21/27 R Warren,Mich. Primary E.\'aminerBarry S. Richman 1 1 "led? 1973 AssistantE.\umincrDale Lovercheck [21] AppL NO; 332,055 Attorney. Agent. orFirm-Arthur E. Kluegel; Richard P. Mueller; B. F. Claeboe [30] ForeignApplication Priority Data [57] ABSTRACT 1972 Germany 2207848 Alkalineconcentrate and aqueous solution for removing lubricant carrier andresidue from iron containing 134/2 134/40 3 0 surfaces. The alkalinesolution contains phosphate ions and either cobalt or nickel ions or amixture of [51] Int. Cl. ..C23g 1/16;C11d7/16;C23g1/20 th t U fth hl I t[58] Field of Search 252/146, 147, 387. 79.1, e be 0 e so u e p5 preen mm 5 age rusting and the problems resulting therefrom.

4 Claims. N0 Drawings METHOD CONCENTRATE AND SOLUTION FOR SIMULTANEOUSCLEANING, DEGREASING AND REMOVAL OF THE LUBRICANT CARRIER LAYER FROMIRON AND STEEL WORKPIECES BACKGROUND OF THE INVENTION Prior to theforming of metal workpieces, it is customary to apply chemical coatings,particularly phosphate layers, to their surfaces, and to carry out theforming in the presence of lubricants. The residues located on thesurface after the forming may interfere with the further processing oruse of the workpieces, so that their removal is necessary.

Aqueous alkaline solutions based on soluble phosphates are often usedfor simultaneous removal (cleaning) of the lubricant carrier layers andthe lubricant residues. Salts of orthophosphoric acid and/or salts ofcondensed phosphates come into consideration as phosphates. However, ithas been found that the treated workpieces are subject to considerabledanger of rusting upon leaving the removal zone, and the rust occursparticularly in the transition zones between processing stages. Thesusceptibility to rust is also at least partially due to the deformationof the workpiece, and thus the change in the surface structure of thematerial. In automatically timed systems, long carry-over times cansometimes intervene between the cleaning bath and the rinsing baths. Theparts cleaned with the phosphate solution rust slightly during thistime. However, this is undesirable and greatly interferes withsubsequent treatments, especially for subsequent phosphation.

THE INVENTION It has not been found that this disadvantageoussusceptibility to rust can be avoided by adding to the cleaning solutionsoluble metal compounds of nickel and/or cobalt, preferably cobalt.

The rust-inhibiting effect is attained upon the addition of at least0.05 g/l of the metal compound, calculated as cobalt and/or nickel.Quantities of more than g/l offer no additional advantage. Preferably,0.1 to 2 g/l of the metal or metals is added.

Suitable cobalt salts include cobalt nitrate, cobalt sulfate, cobaltacetate, cobalt chloride. Suitable nickel compounds include nickelnitrate, nickel sulfate, nickel chloride, nickel acetate.

The phosphates used in the cleaner in accordance with the inventionprimarily include those of condensed phosphoric acids, especiallypyrophosphoric acid. The phosphate content advantageously amounts to 5to 80 g/l, preferably to 50 g/l, calculated as P 0 The aqueous cleaningsolution normally has a pH of 8-13, and preferably the pH is kept in therange of 9-12. In order to increase the cleansing effect of the aqueoussolution, surface-active substances and/or solvents may be included.Suitable surfactants include anionic surfactants such asalkybenzencsulfonates, fatty alcohol sulfates, etc., or nonionicsurfactants, such as ethylene oxide addition products to alkylphenols orfatty alcohols. When nonionic surfactants are used, it is necessary tomake sure that these surfactants possess sufficient solubility at theconcentration and temperature used. Preferably, anionic surfactants areused. It is advantageous to add O.l3 g/l wetting agent. Organicsolvents, such as higherboiling hydrocarbons (kero- 2 sene, petroleum),glycols, or polyglycols are advantageously used in quantities of 0.510g/l.

The cleansing solution in accordance with the inven tion canadvantageously be prepared from a solid cleanser concentrate. Such aconcentrate preferably has the following composition:

907: NzuP o,

O 1071 Na;,P O

0 20% solvent The use of the cleanser in accordance with the inventionwill be explained in greater detail on the basis of the followingexamples:

EXAMPLE I Intermediate stages from shock-absorber piping manufacture,which were covered with a residual phosphate and lubricant layer, werecleaned in a cleanser solution containing 46 g/l Na,P,O calc.

2 g/l Na P O caIc. 1 g/l polyethylene glycol (molecular weight ca. 4000)for 10 min. at C. After this time, the phosphate and lubricant residueswere completely removed from the surface of the workpiece. Following thecleaning, the parts were slowly introduced into a water rinsing bathwithin 60 sec, and rinsed vigorously there.

During the transport of the workpieces from the cleansing bath to thewater rinsing bath, a very thick layer of rust was formed.

In a parallel experiment, 1.24 g/l Co(NO 6 H O (corresponding to 0.25g/l Co) were added to the cleaning solution. In this experiment, noformation of heavy rust on the workpieces occurred.

During the subsequently performed phosphation, when the Co-free cleanerbath was used, phosphate layers flecked irregularly with rust wereformed, and led to substantial disturbances during the subsequent deformation stage. When the Co-containing cleaner bath was used, nodifficulties of this type occurred in the phosphation and shapingprocesses.

EXAMPLE II In order to determine the influence of the Co concentrationon the prevention of heavy rust formation, 0-5 g/l of Co in the form ofcobalt nitrate were added to the cleaning bath according to Example I.In the various cleaning baths, drawing blanks covered with residualphosphate and lubricant layers were cleaned for 10 min at 95C. Thecleaned parts were then kept in the vapor atmosphere of the cleaningbath up to the beginning of heavy rust formation. The experimentalresults thus obtained are presented in the following table.

TABLE Addition. g/l Co Beginning of heavy rust formation after ca....minutes TABLE-continued Addition g/l Co Beginning of heavy rustformation after ca... minutes EXAMPLE lll l. A method for thesimultaneous cleaning, degreasing and removal of a cold-forminglubricant carrier layer from workpieces containing iron comprising con-4 taeting said workpiece with an aqueous alkaline solution comprising5-80 g/l phosphate ion and at least 0.05 g/l of a metal ion selectedfrom the group consisting of cobalt. nickel and mixtures thereof. andhaving a pH adjusted to a value between 8 and 13 for at least oneminute.

2. The method of claim 1 wherein said metal ion is present in aconcentration of from 0.1 to 2.0 g/l.

3. An alkaline phosphate-containing aqueous solution for thesimultaneous cleaning. degreasing and removal of a cold forminglubricant carrier layer from workpieces containing iron, comprising 5-80g/l phosphate ion and at least 0.05 g/l of cobalt ion and having a pHadjusted to a value between 8 and 13.

4. The solution according to claim 3 wherein the cobalt ion is presentin a concentration of aboutOrl to 2.0 g/l.

1. A METHOD FOR THE SIMULTANEOUS CLEANING, DEGREASING AND REMOVAL OF ACOLD-FORMING LUBRICANT CARRIER LAYER FROM WORKPIECES CONTAINING IRONCOMPRISING CONTACTING SAID WORKPIECE WITH AN AQUEOUS ALKALINE SOLUTIONCOMPRISING 5-80 G/L PHOSPHATE ION AND AT LEAST 0.05 G/L OF A METAL IONSELECTED FROM THE GROUP CONSISTING OF COBALT, NICKEL AND MIXTURESTHEREOF, AND HAVING A PH ADJUSTED TO A VALUE BETWEEN 8 AND 13 FOR ATLEAST ONE MINUTE.
 2. The method of claim 1 wherein said metal ion ispresent in a concentration of from 0.1 to 2.0 g/l.
 3. An alkalinephosphate-containing aqueous solution for the simultaneous cleaning,degreasing and removal of a cold forming lubricant carrier layer fromworkpieces containing iron, comprising 5-80 g/l phosphate ion and atleast 0.05 g/l of cobalt ion and having a pH adjusted to a value between8 and
 13. 4. The solution according to claim 3 wherein the cobalt ion ispresent in a concentration of about 0.1 to 2.0 g/l.